The Quran was revealed gradually to Prophet Muhammad (PBUH). After his demise, it existed in various forms, memorized by companions and written on disparate materials. The need for a unified, standardized text became paramount to preserve its authenticity and prevent discrepancies.
The correct answer is Usman (RA). During the caliphate of Usman ibn Affan (RA), significant variations in Quranic recitation emerged across the expanding Islamic empire. To address this, he commissioned a committee to compile a single, authoritative written copy (Mushaf) of the Quran, based on the version collected by Abu Bakr, and ordered all other variant copies to be destroyed. This monumental effort ensured the standardization and preservation of the Quran.
Abu Bakr (RA) initiated the first compilation into a single volume after the Battle of Yamama. Umar (RA) succeeded Abu Bakr but did not undertake the standardization. Ali (RA) was the fourth Caliph, after the standardization was completed.